Method of preparing a starch adhesive and products of the method

Abstract

A method of preparing a starch adhesive ready for use in which a starch bearing, compound is fed to a pressurized system in which the starch is heated, melted, cooled and removed from the pressurized system to comprise an adhesive ready for use. The temperature of the product is maintained above 40° C. to prevent irreversible viscosity increase due to system hysteresis. The adhesive product is especially useful for use in manufacturing corrugated paperboard.

I claim: 
     
       1. A method of preparing an adhesive comprising: supplying a starch bearing composition to a preparation system and placing the composition under pressure;   heating the starch bearing composition while under pressure at least to the melting point of the composition; then   cooling the composition while still under pressure to a temperature below about 150° C. but not below about 100° C. to provide an adhesive ready for use or further compounding.   
     
     
       2. The method of claim 1 in which the starch bearing composition is further cooled to a temperature below about 100° C. but not below about 40° C. and removing the composition from the pressure zone of the system to provide an adhesive ready for use or further compounding.   
     
     
       3. The method of claim 2 further comprising adding ungelatinized starch to the melted and cooled starch composition while maintaining the compounded mixture above a temperature of about 40° C. to provide an adhesive ready for use. 
     
     
       4. The method of claim 1 in which the starch bearing composition is comprised of essentially ungelatinized starch. 
     
     
       5. A product made by the method of claim 1.